1. Field of the Invention
The present invention relates to a storage system and a storage control device.
2. Description of the Related Art
For example, in a database system handling a large-scale data such as a data center, data is controlled using a storage system configured separately from a host computer. The storage system includes, for example, a disk array system. The disk array system includes a number of disk storage units disposed in an array, and is established based for example on RAID (Redundant Array of Independent Inexpensive Disks). At least one logical volume is formed in a physical storage area provided by a group of disk units, and the logical volume is provided to a host computer (more specifically, to a database program operated on the host computer). The host computer can execute writing and reading of data with respect to the logical volume by transmitting a predetermined command.
In accordance with development of information society, data to be controlled by databases increases day by day. Therefore, a storage control device of higher capability and of larger volume is desired. In order to meet such market requirement, new types of storage control devices have been developed. There are two conceivable methods for introducing the new storage control devices into the storage system. One is a method to configure a storage system with all new types of storage control devices (JP-T-10-508967) by entirely replacing an old type of storage control device with a new type of storage control device. The other one is a method to add a new type of storage control device to the storage system including an old type of storage control device to allow the old and new types of storage control devices to coexist.
When transferring completely from the old type of storage control device to the new type of storage control device (Patent Document 1), although functions and capabilities of the new type of storage control device can be utilized, the old type of storage control device cannot be used effectively. On the other hand, when attempt is made to allow the old type of storage control device and the new type of storage control device to coexist, the number of storage control devices configuring the storage system increases, and thus control and operation of the old and new types of storage control devices are complex.